A basal contribution from p-modes to the Alfvénic wave flux in the Sun’s corona


Many cool stars possess complex magnetic fields1 that are considered to undertake a central role in the structuring and energizing of their atmospheres2. Alfvénic waves are thought to make a critical contribution to energy transfer along these magnetic fields, with the potential to heat plasma and accelerate stellar winds3,4,5. Despite Alfvénic waves having been identified in the Sun’s atmosphere, the nature of the basal wave energy flux is poorly understood. It is generally assumed that the associated Poynting flux is generated solely in the photosphere and propagates into the corona, typically through the continuous buffeting of magnetic fields by turbulent convective cells4,6,7. Here, we provide evidence that the Sun’s internal acoustic modes also contribute to the basal flux of Alfvénic waves, delivering a spatially ubiquitous input to the coronal energy balance that is sustained over the solar cycle. Alfvénic waves are thus a fundamental feature of the Sun’s corona. Acknowledging that internal acoustic modes have a key role in injecting additional Poynting flux into the upper atmospheres of Sun-like stars has potentially significant consequences for the modelling of stellar coronae and winds.

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Fig. 1: Signature of coronal Alfvénic waves.
Fig. 2: Properties of Alfvénic waves throughout the corona.
Fig. 3: Power spectra parameter distributions for Alfvénic waves.
Fig. 4: Global measures of Alfvénic waves through the solar cycle.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request. The SDO data are available from the Joint Science Operations Center (http://jsoc.stanford.edu). The CoMP data are available from the High Altitude Observatory data repository (https://www2.hao.ucar.edu/mlso/mlso-home-page).


  1. 1.

    Reiners, A. Observations of cool-star magnetic fields. Living Rev. Sol. Phys. 9, 1 (2012).

    ADS  Article  Google Scholar 

  2. 2.

    Testa, P., Saar, S. H. & Drake, J. J. Stellar activity and coronal heating: an overview of recent results. Phil. Trans. R. Soc. A 373, 20140259 (2015).

    ADS  Article  Google Scholar 

  3. 3.

    Narain, U. & Ulmschneider, P. Chromospheric and coronal heating mechanisms II. Space Sci. Rev. 75, 453–509 (1996).

    ADS  Article  Google Scholar 

  4. 4.

    Suzuki, T. K. & Inutsuka, S. Making the corona and the fast solar wind: a self-consistent simulation for the low-frequency Alfvén waves from the photosphere to 0.3au. Astrophys. J. 632, L49–L52 (2005).

    ADS  Article  Google Scholar 

  5. 5.

    Verdini, A. & Velli, M. Alfvén waves and turbulence in the solar atmosphere and solar wind. Astrophys. J. 662, 669–676 (2007).

    ADS  Article  Google Scholar 

  6. 6.

    Cranmer, S. R. & van Ballegooijen, A. A. On the generation, propagation, and reflection of Alfvén waves from the solar photosphere to the distant heliosphere. Astrophys. J. Suppl. Ser. 156, 265–293 (2005).

    ADS  Article  Google Scholar 

  7. 7.

    Van Ballegooijen, A. A., Asgari-Targhi, M., Cranmer, S. R. & DeLuca, E. E. Heating of the solar chromosphere and corona by Alfvén wave turbulence. Astrophys. J. 736, 3 (2011).

    ADS  Article  Google Scholar 

  8. 8.

    Belcher, J. W. & Davis, L. J. Large-amplitude Alfvén waves in the interplanetary medium 2. J. Geophys. Res. 76, 3534–3563 (1971).

    ADS  Article  Google Scholar 

  9. 9.

    Bruno, R. & Carbone, V. The solar wind as a turbulence laboratory. Living Rev. Sol. Phys. 2, 4 (2005).

    ADS  Article  Google Scholar 

  10. 10.

    Banerjee, D., Teriaca, L., Doyle, J. G. & Wilhelm, K. Broadening of SI VIII lines observed in the solar polar coronal holes. Astron. Astrophys. 339, 208–214 (1998).

    ADS  Google Scholar 

  11. 11.

    Tomczyk, S. et al. Alfvén waves in the solar corona. Science 317, 1192–1196 (2007).

    ADS  Article  Google Scholar 

  12. 12.

    De Pontieu, B. et al. Chromospheric Alfvénic waves strong enough to power the solar wind. Science 318, 1574–1577 (2007).

    ADS  Article  Google Scholar 

  13. 13.

    Morton, R. J., Tomczyk, S. & Pinto, R. F. Investigating Alfvénic wave propagation in coronal open-field regions. Nat. Commun. 6, 7813 (2015).

    ADS  Article  Google Scholar 

  14. 14.

    Morton, R. J., Tomczyk, S. & Pinto, R. F. A global view of velocity fluctuations in the corona below 1.3 R with CoMP. Astrophys. J. 828, 89 (2016).

    ADS  Article  Google Scholar 

  15. 15.

    Van Doorsselaere, T., Nakariakov, V. M. & Verwichte, E. Detection of waves in the solar corona: kink or Alfvén? Astrophys. J. Lett. 676, L73 (2008).

    ADS  Article  Google Scholar 

  16. 16.

    McIntosh, S. W. et al. Alfvénic waves with sufficient energy to power the quiet solar corona and fast solar wind. Nature 475, 447–480 (2011).

    ADS  Article  Google Scholar 

  17. 17.

    Thurgood, J. O., Morton, R. J. & McLaughlin, J. A. First direct measurements of transverse waves in solar polar plumes using SDO/AIA. Astrophys. J. 790, L2 (2014).

    ADS  Article  Google Scholar 

  18. 18.

    Cally, P. S. & Goossens, M. Three-dimensional MHD wave propagation and conversion to Alfvén waves near the solar surface. I. Direct numerical solution. Sol. Phys. 251, 251–265 (2008).

    ADS  Article  Google Scholar 

  19. 19.

    Cally, P. S. & Hansen, S. C. Benchmarking fast-to-Alfvén mode conversion in a cold magnetohydrodynamic plasma. Astrophys. J. 738, 119 (2011).

    ADS  Article  Google Scholar 

  20. 20.

    Cally, P. S. Alfvén waves in the structured solar corona. Mon. Not. R. Astron. Soc. 466, 413–424 (2017).

    ADS  Article  Google Scholar 

  21. 21.

    Jefferies, S. M. et al. Magnetoacoustic portals and the basal heating of the solar chromosphere. Astrophys. J. 648, L151–L155 (2006).

    ADS  Article  Google Scholar 

  22. 22.

    Matthaeus, W. H., Zank, G. P., Oughton, S., Mullan, D. J. & Dmitruk, P. Coronal heating by magnetohydrodynamic turbulence driven by reflected low-frequency waves. Astrophys. J. 523, L93–L96 (1999).

    ADS  Article  Google Scholar 

  23. 23.

    Bavassano, B., Dobrowolny, M., Mariani, F. & Ness, N. F. Radial evolution of power spectra of interplanetary Alfvénic turbulence. J. Geophys. Res. 87, 3617–3622 (1982).

    ADS  Article  Google Scholar 

  24. 24.

    Pandey, B. P., Vranjes, J. & Krishan, V. Waves in the solar photosphere. Mon. Not. R. Astron. Soc. 386, 1635–1643 (2008).

    ADS  Article  Google Scholar 

  25. 25.

    Soler, R., Ballester, J. L. & Zaqarashvili, T. V. Overdamped Alfvén waves due to ion-neutral collisions in the solar chromosphere. Astron. Astrophys. 573, 79 (2015).

    ADS  Article  Google Scholar 

  26. 26.

    Arber, T. D., Brady, C. S. & Shelyag, S. Alfvén wave heating of the solar chromosphere: 1.5D models. Astrophys. J. 817, 94 (2016).

    ADS  Article  Google Scholar 

  27. 27.

    Morgan, H. & Taroyan, Y. Global conditions in the solar corona from 2010 to 2017. Sci. Adv. 3, e1602056 (2017).

    ADS  Article  Google Scholar 

  28. 28.

    McIntosh, S. W. & De Pontieu, B. Estimating the “dark” energy content of the solar corona. Astrophys. J. 761, 138 (2012).

    ADS  Article  Google Scholar 

  29. 29.

    Chaplin, W. J. & Miglio, A. Asteroseismology of solar-type and red-giant stars. Annu. Rev. Astron. Astrophys. 51, 353–392 (2013).

    ADS  Article  Google Scholar 

  30. 30.

    Tomczyk, S. et al. An instrument to measure coronal emission line polarization. Sol. Phys. 247, 411–428 (2008).

    ADS  Article  Google Scholar 

  31. 31.

    Lemen, J. R. et al. The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). Sol. Phys. 275, 17–40 (2012).

    ADS  Article  Google Scholar 

  32. 32.

    Goossens, M., Terradas, J., Andries, J., Arregui, I. & Ballester, J. L. On the nature of kink MHD waves in magnetic flux tubes. Astron. Astrophys. 503, 213–223 (2009).

    ADS  Article  Google Scholar 

  33. 33.

    Goossens, M. et al. Surface Alfvén waves in solar flux tubes. Astrophys. J. 753, 111 (2012).

    ADS  Article  Google Scholar 

  34. 34.

    Weberg, M., Morton, R. J. & McLaughlin, J. A. An automated algorithm for identifying and tracking transverse waves in solar images. Astrophys. J. 852, 57 (2018).

    ADS  Article  Google Scholar 

  35. 35.

    Vaughan, S. A simple test for periodic signals in red noise. Astron. Astrophys. 431, 391–403 (2005).

    ADS  Article  Google Scholar 

  36. 36.

    Ireland, J., McAteer, R. T. J. & Inglis, A. R. Coronal Fourier power spectra: implications for coronal seismology and coronal heating. Astrophys. J. 798, 12 (2015).

    Google Scholar 

  37. 37.

    Feigelson, E. & Babu, G. J. Modern Statistical Methods for Astronomy (Cambridge Univ. Press, Cambridge, 2012).

  38. 38.

    De Pontieu, B. et al. The origins of hot plasma in the solar corona. Science 331, 55–58 (2011).

    ADS  Article  Google Scholar 

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All authors acknowledge that this material is based on work supported by the Air Force Office of Scientific Research, Air Force Material Command, USAF under award number FA9550-16-1-0032, and the Science and Technology Facilities Council via grant number ST/L006243/1. R.J.M. is grateful to the Leverhulme Trust for the award of an Early Career Fellowship, and the High Altitude Observatory for financial assistance. M.J.W. acknowledges additional support from NASA grant NNH16AC39I and basic research funds from the Chief of Naval Research. R.J.M. is also grateful for discussions at ISSI, Bern (Towards Dynamic Solar Atmospheric Magneto-Seismology with New Generation Instrumentation) and with G. Li and S. Tomczyk. The authors acknowledge the work of the NASA/SDO and AIA science teams, and National Center for Atmospheric Research/High Altitude Observatory CoMP instrument team.

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R.J.M. performed the analysis of the CoMP data. R.J.M., M.J.W. and J.A.M. performed the analysis of the SDO data. All authors discussed the results and contributed to the writing of the manuscript.

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Correspondence to R. J. Morton.

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Morton, R.J., Weberg, M.J. & McLaughlin, J.A. A basal contribution from p-modes to the Alfvénic wave flux in the Sun’s corona. Nat Astron 3, 223–229 (2019). https://doi.org/10.1038/s41550-018-0668-9

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